Jesse Snedeker

Using prosody to avoid ambiguity : Effects of speaker awareness and referential context

Abstract In three experiments, a referential communication task was used to determine the conditions under which speakers produce and listeners use prosodic cues to distinguish alternative meanings of a syntactically ambiguous phrase. Analyses of the actions and utterances from Experiments 1 and 2 indicated that Speakers chose to produce effective prosodic cues to disambiguation only when the referential scene provided support for both interpretations of the phrase. In Experiment 3, on-line measures of parsing commitments were obtained by recording the Listener’s eye movements to objects as the Speaker gave the instructions. Results supported the previous experiments but also showed that the Speaker’s prosody affected the Listener’s interpretation prior to the onset of the ambiguous phrase, thus demonstrating that prosodic cues not only influence initial parsing but can also be used to predict material which has yet to be spoken. The findings suggest that informative prosodic cues depend upon speakers’ knowledge of the situation: speakers provide prosodic cues when needed; listeners use these prosodic cues when present.

The developing constraints on parsing decisions: The role of lexical-biases and referential scenes in child and adult sentence processing

Two striking contrasts currently exist in the sentence processing literature. First, whereas adult readers rely heavily on lexical information in the generation of syntactic alternatives, adult listeners in world-situated eye-gaze studies appear to allow referential evidence to override strong countervailing lexical biases (Tanenhaus, Spivey-Knowlton, Eberhard, and Sedivy, 1995). Second, in contrast to adults, children in similar listening studies fail to use this referential information and appear to rely exclusively on verb biases or perhaps syntactically based parsing principles (Trueswell, Sekerina, Hill, and Logrip, 1999). We explore these contrasts by fully crossing verb bias and referential manipulations in a study using the eye-gaze listening technique with adults (Experiment 1) and five-year-olds (Experiment 2). Results indicate that adults combine lexical and referential information to determine syntactic choice. Children rely exclusively on verb bias in their ultimate interpretation. However, their eye movements reveal an emerging sensitivity to referential constraints. The observed changes in information use over ontogenetic time best support a constraint-based lexicalist account of parsing development, which posits that highly reliable cues to structure, like lexical biases, will emerge earlier during development and more robustly than less reliable cues.

How words can and cannot be learned by observation.

Three experiments explored how words are learned from hearing them across contexts. Adults watched 40-s videotaped vignettes of parents uttering target words (in sentences) to their infants. Videos were muted except for a beep or nonsense word inserted where each “mystery word” was uttered. Participants were to identify the word. Exp. 1 demonstrated that most (90%) of these natural learning instances are quite uninformative, whereas a small minority (7%) are highly informative, as indexed by participants’ identification accuracy. Preschoolers showed similar information sensitivity in a shorter experimental version. Two further experiments explored how cross-situational information helps, by manipulating the serial ordering of highly informative vignettes in five contexts. Response patterns revealed a learning procedure in which only a single meaning is hypothesized and retained across learning instances, unless disconfirmed. Neither alternative hypothesized meanings nor details of past learning situations were retained. These findings challenge current models of cross-situational learning which assert that multiple meaning hypotheses are stored and cross-tabulated via statistical procedures. Learners appear to use a one-trial “fast-mapping” procedure, even under conditions of referential uncertainty.

Give and take: Syntactic priming during spoken language comprehension

Syntactic priming during language production is pervasive and well-studied. Hearing, reading, speaking or writing a sentence with a given structure increases the probability of subsequently producing the same structure, regardless of whether the prime and target share lexical content. In contrast, syntactic priming during comprehension has proven more elusive, fueling claims that comprehension is less dependent on general syntactic representations and more dependent on lexical knowledge. In three experiments we explored syntactic priming during spoken language comprehension. Participants acted out double-object (DO) or prepositional-object (PO) dative sentences while their eye movements were recorded. Prime sentences used different verbs and nouns than the target sentences. In target sentences, the onset of the direct-object noun was consistent with both an animate recipient and an inanimate theme, creating a temporary ambiguity in the argument structure of the verb (DO e.g., Show the horse the book; PO e.g., Show the horn to the dog). We measured the difference in looks to the potential recipient and the potential theme during the ambiguous interval. In all experiments, participants who heard DO primes showed a greater preference for the recipient over the theme than those who heard PO primes, demonstrating across-verb priming during online language comprehension. These results accord with priming found in production studies, indicating a role for abstract structural information during comprehension as well as production.

Relatives Children Say

In an experiment designed to elicit restrictive relatives clauses, 28 children ranging in age from 2:2 to 3:10 provided a corpus of communicatively appropriate relative clauses. In evaluating this corpus, we found that most children produced mostly adult relative clauses most of the time. Detailed study of these utterances uncovered a few error patterns, which we analyzed in light of several considerations (e.g., the overall frequency of an error type, its distribution across children and items, its relation to the construction under study, and the similarity of the error to what children do elsewhere). Only one error pattern, namely some childrens production of inappropriate relative pronouns, is argued to reflect a systematic feature of language development. We conclude that childrens ability to represent the syntactic structure of the embedded clause is on target very early.

Starting Over International Adoption as a Natural Experiment in Language Development

Language development is characterized by predictable shifts in the words children produce and the complexity of their utterances. Because acquisition typically occurs simultaneously with maturation and cognitive development, it is difficult to determine the causes of these shifts. We explored how acquisition proceeds in the absence of possible cognitive or maturational roadblocks, by examining the acquisition of English in internationally adopted preschoolers. Like infants, and unlike other second-language learners, these children acquire language from child-directed speech, without access to bilingual informants. Parental reports and speech samples were collected from 27 preschoolers, 3 to 18 months after they were adopted from China. These children showed the same developmental patterns in language production as monolingual infants (matched for vocabulary size). Early on, their vocabularies were dominated by nouns, their utterances were short, and grammatical morphemes were generally omitted. Children at later stages had more diverse vocabularies and produced longer utterances with more grammatical morphemes.

What exactly do numbers mean

Number words are generally used to refer to the exact cardinal value of a set, but cognitive scientists disagree about their meanings. Although most psychological analyses presuppose that numbers have exact semantics (two means exactly two), many linguistic accounts propose that numbers have lower-bounded semantics (at least two), and that speakers restrict their reference through a pragmatic inference (scalar implicature). We address this debate through studies of children who are in the process of acquiring the meanings of numbers. Adults and 2- and 3-year-olds were tested in a novel paradigm that teases apart semantic and pragmatic aspects of interpretation (the covered box task). Our findings establish that when scalar implicatures are cancelled in the critical trials of this task, both adults and children consistently give exact interpretations for number words. These results, in concert with recent work on real-time processing, provide the first unambiguous evidence that number words have exact semantics.

Logic and Conversation Revisited: Evidence For a Division Between Semantic and Pragmatic Content in Real Time Language Comprehension

The distinction between semantics (linguistically encoded meaning) and pragmatics (inferences about communicative intentions) can often be unclear and counterintuitive. For example, linguistic theories argue that the meaning of some encompasses the meaning of all while the intuition that some implies not all results from an inference. We explored how online interpretation of some evolves using an eye-tracking while listening paradigm. Early eye-movements indicated that while some was initially interpreted as compatible with all, participants began excluding referents compatible with all approximately 800 ms later. These results contrast with recent evidence of immediate inferencing and highlight the presence of bottom-up semantic–pragmatic interactions which necessarily rely on initial access to lexical meanings to trigger inferences.

When Is Four Far More Than Three? Children’s Generalization of Newly Acquired Number Words

What is the relationship between children’s first number words and number concepts? We used training tasks to explore children’s interpretation of number words as they acquired the words’ meanings. Children who had mastered the meanings of only the first two or three number words were systematically provided with varied input on the next word-to-quantity mapping, and their extension of the newly trained word was assessed across a variety of test items. Children who had already mastered number words to three generalized training on four to new objects and nouns, such that their representation of the newly learned number was approximate. In contrast, children who had mastered only one and two learned to apply three reliably within a single count-noun context (e.g., three dogs), but did not generalize training to new objects labeled with different nouns (e.g., three cows). Both findings suggest that children fail to map newly learned words in their counting routine to the fully abstract concepts of natural numbers.

Mutual exclusivity in autism spectrum disorders: Testing the pragmatic hypothesis

While there is ample evidence that children treat words as mutually exclusive, the cognitive basis of this bias is widely debated. We focus on the distinction between pragmatic and lexical constraints accounts. High-functioning children with autism spectrum disorders (ASD) offer a unique perspective on this debate, as they acquire substantial vocabularies despite impoverished social-pragmatic skills. We tested children and adolescents with ASD in a paradigm examining mutual exclusivity for words and facts. Words were interpreted contrastively more often than facts. Word performance was associated with vocabulary size; fact performance was associated with social-communication skills. Thus mutual exclusivity does not appear to be driven by pragmatics, suggesting that it is either a lexical constraint or a reflection of domain-general learning processes.